Author: Alan Reiner 2011-11-23 15:35:06
Published on: 2011-11-23T15:35:06+00:00
In a discussion on Bitcoin development in 2011, Gavin Andresen pointed out the dangers of a "hardest block found in X minutes" scheme. He argued that if someone were to find an extremely hard block, they would have an incentive to keep it secret and build more blocks on top of it before announcing them all at once. If the rest of the network rejected the longer chain because the block was not announced in a timely fashion, the network could be split irreparably. In contrast, Bitcoin at the time used the difficulty target to compute chain difficulty instead of actual hashes found, which prevented this problem. Alan provided evidence for Gavin's point, citing a block with a difficulty of 36 billion when the network had a difficulty of 1.5 million, making it 24,000 times harder than the target. He suggested that if one were going by the actual hardest chain instead of the target-based hardest chain, this block might still represent the longest chain. This meant that whoever produced the block could have held onto it for several months and then broadcast it to fork the blockchain from a block produced months ago. Alan warned that this was not theoretical but real data in the blockchain and a potential disaster.
Updated on: 2023-06-04T21:32:21.303176+00:00